The present invention relates to a device which generates electric signals and more particularly the invention relates to a signal generator which is integrated into the structural elements of an existing functional apparatus such as an automobile fender, a deck lid or a trim piece.
During the past several years electric signals produced with piezoelectric materials have been considered for use in automobiles, elevators, telephones, appliances, and similar type products. U.S. Pat. No. 4,206,491 entitled "Entry System" describes an overall apparatus which could include a piezoelectric signal generator of the type disclosed in U.S. Pat. No. 4,190,785 entitled "Pressure Sensitive Signal Generator Using Piezoelectric Coatings." Further, when used in harsh environments particularly in automotive applications, the signal generator may appear as an embodiment as is disclosed in the U.S. Patent entitled "Encased Piezoelectric Signal Generator" which is filed concurrently with the present application and is assigned to a common assignee.
In some applications requiring the generation of electric signals, the signal generator is preferably attached to the surrounding environment in a manner which is cosmetically appealing or maybe even undetectable. This would be the case in an application involving an automobile hood, truck or door lock. An undetectable attachment means might be especially desirable, if the signal generator application is the deactivation of a burglar alarm system on an automobile.
In addition to the inconspicuousness requirement of some applications, a signal generator, is often faced with severe location requirements particularly in the automotive environment. The industry is experiencing an overall effort to reduce the size and weight of automobiles and to more efficiently utilize the resulting space in any particular design. These factors, in addition to the distinct trend toward greater sophistication and additional accessory features in automobiles very often results in demanding specifications in the form of components which are small and lightweight but rugged and durable.